Greatest possible error
key notes :
Definition
- The Greatest Possible Error (GPE) is the maximum amount by which a measured value could differ from the true value due to limitations of the measuring instrument.
- It represents the uncertainty of a measurement.
How to Calculate GPE
- The GPE is half of the smallest measurement unit of the instrument used.
- Formula:
Greatest Possible Error = Smallest Division of the Instrument / 2
- Example: If a ruler measures in millimeters (mm), the GPE is 1/2 mm = 0.5 mm.
Why GPE Matters
- Helps understand the accuracy and precision of measurements.
- Essential in fields like science, engineering, and construction, where exact measurements are crucial.
Absolute Error vs. Relative Error
- Absolute Error: The GPE expressed in measurement units (e.g., ±0.5 cm).
- Relative Error: The GPE divided by the measured value, often expressed as a percentage.
Example Problem
If you measure a table’s length as 100 cm using a ruler with 1 cm divisions:
GPE = 1 cm / 2 = 0.5 cm
The actual length could be between 99.5 cm and 100.5 cm.
Importance in Real-Life Scenarios
- In construction, small errors can lead to significant structural problems.
- In scientific experiments, GPE helps determine the confidence level of results.
Key Terms to Remember
- Precision: How detailed a measurement is.
- Accuracy: How close a measurement is to the true value.
- Uncertainty: The range in which the true value is expected to lie.
Learn with an example
🔮 What is the greatest possible error for a measurement of 8 tonnes?
____tonnes
- The measurement of 8 metric tons was made to the nearest whole metric ton.
- The greatest possible error is half of 1 metric ton, which is 0.5 metric tons.
🔮 What is the greatest possible error for a measurement of 5 centimetres?______centimetres
- The measurement of 5 centimetres was made to the nearest whole centimetre.
- The greatest possible error is half of 1 centimetre, which is 0.5 centimetres.
🔮What is the greatest possible error for a measurement of 8 centimetres? ______centimetres
- The measurement of 8 centimetres was made to the nearest whole centimetre.
- The greatest possible error is half of 1 centimetre, which is 0.5 centimetres.
Let’s practice!🖊️